Taking a kindergarten in Lanzhou as an example, this study systematically analyzes the thermal comfort of the activity space of young children under three kinds of weather: sunny day, cloudy day, and floating dust, by using the PMV-PPD model combined with the parameters of temperature and humidity, wind speed, and radiation temperature. The measured data show that the thermal environment fluctuates the least in dusty weather, the thermal comfort index changes the most stably in sunny days, and the physical sensation is moderately cold in cloudy days. One-way regression analysis showed that the operating temperature had the most significant effect on PMV in dusty weather, and the model fit was the highest in sunny days. The study provides a scientific basis for optimizing the design of the thermal environment in kindergartens.